package com.qiyu.dubbo.common;

import java.text.DecimalFormat;

public class ConsoleProgressBarDemo {

	/**
	 * 进度条长度
	 */
	private int barLen;

	/**
	 * 用于进度条显示的字符
	 */
	private char showChar;

	private DecimalFormat formater = new DecimalFormat("#.##%");

	/**
	 * 使用系统标准输出，显示字符进度条及其百分比
	 */
	public ConsoleProgressBarDemo(int barLen, char showChar) {
		this.barLen = barLen;
		this.showChar = showChar;
	}

	/**
	 * 显示进度条
	 */
	public void show(int value) {
		if (value < 0 || value > 100) {
			return;
		}

		reset();

		// 比例
		float rate = (float) (value*1.0 / 100);
		// 比例*进度条总长度=当前长度
		draw(barLen, rate);
		if (value == 100L) {
			afterComplete();
		}
	}

	/**
	 * 画指定长度个showChar
	 */
	private void draw(int barLen, float rate) {
		int len = (int) (rate * barLen);
		System.out.print("Progress: ");
		for (int i = 0; i < len; i++) {
			System.out.print(showChar);
		}
		for (int i = 0; i < barLen-len; i++) {
			System.out.print(" ");
		}
		System.out.print(" |" + format(rate));
	}


	/**
	 * 光标移动到行首
	 */
	private void reset() {
		System.out.print('\r');
	}

	/**
	 * 完成后换行
	 */
	private void afterComplete() {
		System.out.print('\n');
	}

	private String format(float num) {
		return formater.format(num);
	}

    public static void main(String[] args) throws InterruptedException {
		ConsoleProgressBarDemo cpb = new ConsoleProgressBarDemo(50, '█');
        for (int i = 1; i <= 100; i++) {
            cpb.show(i);
            Thread.sleep(100);
        }
    }

}

